The present invention relates to heterocyclic compounds, and more particularly, to methods for the preparation of new 6-aminopenicillanic acid derivatives.
These compounds belongs to the group of semisynthetic penicillins. Known semisynthetic penicillins and methycillin, ampicillin, and oxacillin used in medical practice do not possess all of the desired properties, namely, a wide-range efficiency and combined acid- and penicillinase resistance. Thus, methycillin, while being penicillinase resistant, is not acid-resistant so that changes in various tissues and organs (especially in kidneys) occur after prolonged usage thereof.
In addition, the methods for preparing methycillin, as well as other preparations, are complicated and require many stages. The above-mentioned compounds are prepared by acylating 6-aminopenicillanic acid with acylating agents, such as 2,6-dimethoxy-benzoic acid, .alpha. -amino benzoic acid and phenylisoxasolyl carboxylic acid. These acylating agents require, in turn, a complicated synthesis process which cannot give a good yield of the desired product.